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This GNU Radio component implements a monostatic radar transmitter
and receiver. It uses a custom FPGA build to generate a linear
FM chirp waveform directly in the USRP. Echo returns are recorded
to a file for offline analysis.
The LFM chirp can be up to 32 MHz in width, whose center frequency
is set by which transmit daughter board is installed. This gives
a range resolution of approximately 5 meters.
The script to run is placed in $prefix/bin:
Usage: usrp_radar_mono.py [options]
Options:
-h, --help show this help message and exit
-T TX_SUBDEV_SPEC, --tx-subdev-spec=TX_SUBDEV_SPEC
use transmitter board side A or B (default is first
found)
-R RX_SUBDEV_SPEC, --rx-subdev-spec=RX_SUBDEV_SPEC
use receiver board side A or B (default is first
found)
-g GAIN, --gain=GAIN set gain in dB (default is midpoint)
-f FREQ, --frequency=FREQ
set transmitter center frequency to FREQ in Hz,
default is 0.0
-w FREQ, --chirp-width=FREQ
set LFM chirp bandwidth in Hz, default is 32M
-a AMPLITUDE, --amplitude=AMPLITUDE
set waveform amplitude in % full scale, default is 15,
--ton=TON set pulse on period in seconds, default is 5e-06,
--tsw=TSW set transmitter switching period in seconds, default
is 4.0625e-07,
--tlook=TLOOK set receiver look time in seconds, default is 5e-06,
--prf=PRF set pulse repetition frequency in Hz, default is
10000.0,
-v, --verbose enable verbose output, default is disabled
-D, --debug enable debugging output, default is disabled
-F FILENAME, --filename=FILENAME
log received echos to file
The transmitter creates an LFM chirp, evenly centered on the supplied frequency.
The four timing parameters are:
ton Chirp on time in seconds.
tsw Transmitter switching time in seconds. This the delay after the chirp
is transmitted before the receiver is enabled. These two (tsw and ton)
parameters determine the minimum range of the radar.
tlook The the amount of time in seconds the receiver is enabled to record
echo responses ("look" time). This parameter determines the maximum
radar range that can be measured, though transmitter power will also
limit return strength and practical range.
prf Pulse repetition frequency in Hz. This establishes to overall pulse
repetition period, which results in idle time between when the receiver
is turned off and the next transmitted chirp begins.
The transmitter is completed. The receive path is logging echo data to a supplied
file; however, no meta-data is logged.
This is experimental code.
Johnathan Corgan
Corgan Enterprises LLC
jcorgan@corganenterprises.com
9/17/2007
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